Apparatus for forming electrode of chip-like electronic part

ABSTRACT

An electrode is formed on a chip-like electronic part of the type having a central axis, a polygonal cross section as viewed in a plane which is perpendicular to the central axis, a plurality of side surfaces extending in respective planes which are generally parallel to the central axis, and a pair of end surfaces extending generally parallel to the central axis, each adjacent pair of side surfaces meeting along a respective edge of the chip-like electronic part. The electrode is formed by applying a first band of conductive material to at least one of the side surfaces and applying a second band of conductive material to the remaining side surface(s) in such a manner that the first and second bands meet at respective ones of the edges and together form a continuous band of conductive material extending around the outer periphery of the chip-type electronic part. The chip-like electronic part is held by a holder with a first plurality of side surfaces being exposed and facing a paste base on which a streak of conductive material is placed. The holder and paste base are brought together so that the first band of conductive material is applied to the first plurality of side surfaces. The chip-like electronic part is then repositioned with its remaining side surfaces being exposed and facing a paste base and the second band of conductive material is applied to those side surfaces.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This is a divisional of U.S. Pat. application Ser. No.09/122,145, filed Jul. 24, 1998 in the name of Tadahiro Nakagawa et al.and entitled “PROCESS OF FORMING ELECTRODE OF CHIP ELECTRONIC PART.”

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a process of forming anelectrode for a chip-like electronic part and a holder for a chip-likeelectronic part, particularly to a process of forming an electrodecomprising a conductive paste on an outer surface of a chip-likeelectronic part and a holder for a chip-like electronic part preferablyused in carrying out the process.

[0004] 2. Description of Related Art

[0005]FIG. 18 shows a perspective view of a chip-like electronic part 1,particularly a three terminal capacitor. End electrodes 2 and 3 areformed on respective end portions of the chip-like electronic part 1 andcentral electrodes 4 are formed at the central portion thereof.

[0006] Although not illustrated, first and second groups of innerelectrodes are arranged alternately inside the chip-like electronic part1 with the inner electrodes of the first group extending to the endelectrodes 2 and 3 and the inner electrodes of the second groupextending to the central electrodes 4. Accordingly, electrostaticcapacitances formed between the inner electrodes of the first group andthe inner electrodes of the second group can be taken out between theend electrode 2 or 3 and the central electrodes 4. The chip-likeelectronic part 1 is used to, for example, remove noise on a signal lineby coupling the end electrodes 2 and 3 to the signal line and groundingthe central electrodes 4.

[0007] As shown in FIG. 18, the central electrodes 4 extend across twoopposing side faces of the chip-like electronic part 1. Because oflimitations associated with the process commonly used to make thechip-like electronic part 1, the central electrodes 4 extend onlypartially on the other side faces of the chip-like electronic part. As aresult, the central electrodes 4 do not extend entirely around the outerside surfaces of the chip-like electronic part 1.

[0008] The process for applying the central electrodes 4 is bestunderstood with reference to FIG. 19. As shown herein, a groove 6 isprovided in a paste base 5 which comprises an elastic body. The groove 6is filled with a conductive paste 7 to form an elongated streak 8 ofconductive paste 3. The chip-like electronic part 1 is held by a holder9 so that one face of the chip-like electronic part 1 faces the streak 8of conductive paste.

[0009] As best seen in FIG. 18, the chip-like electronic part 1 is anelongated parallel-piped structure having a main axis extending from endelectrode 2 to end electrode 3. The central portion of the chip-likeelectronic part 1 is aligned with the streak 8 of conductive paste withthe axis of the streak extending perpendicular to the central axis ofthe chip-like electronic part 1. The chip-like electronic part 1 isbrought into contact with the paste base 5 and pressed against the pastebase 5 to deform it and cause the conductive paste 7 to be applied tothe outer surface of the chip-like electronic part 1 as shown by animaginary line in FIG. 19. Although the conductive paste 7 extendsacross the entire side face of the chip-like electronic part 1 whichfaces the base 5, it only extends partway up the adjacent side faces ofthe chip-like electronic part 1.

[0010] The orientation of the chip-like electronic part 1 is thenreversed so that its opposite face extends away from the holder andtowards the paste base 5 and the process is repeated to place theconductive paste 7 on the opposite face (and particularly up theadjacent side faces) of the chip-like electronic part 1. Thereafter, theso applied central electrodes 4 are cured.

[0011] Instead of placing the conductive paste 7 in a groove 6 providedin the elastic paste base 5, the conductive paste may be applied (byprinting or the like) on a flat face of a paste base 5 which can beeither elastic or rigid. As another alternative, a reservoir ofconductive paste located on one side of a slit plate can be extruded tothe other side of the slit plate via the slit in the plate by applyingpressure to the conductive paste.

[0012] The end electrodes 2 and 3 are formed by dipping the ends of thechip-like electronic part 1 into a tank of conductive paste.

[0013] As mentioned above, the central electrode 4 does not normallyextend around the entire outer surface of the chip-like electronic part1. However, it is preferable that it does to reduce unnecessaryinductance components where the central electrode is used as a groundelectrode.

[0014] It is not impossible to form the central electrode to extendaround the entire circumference of the chip-like electronic part 1 usingthe process shown in FIG. 19. This result can be achieved by providing asufficient amount of conductive paste to extend at least half way up thetwo side faces of the chip-like electronic part 1, for example, bymaking the groove deeper or pressing the chip-like electronic part 1more strongly against the paste base 5. However, as shown in thesectional view of FIG. 20, overlap portions 12 are formed on flat endfaces of the chip-like electronic part. These overlap portions 12 canhamper the mountability of the chip-like electronic part. Accordingly,it is preferable that a built-up portion, such as the overlap portion12, not be formed at the central portion of any of the side faces of thechip-like electronic part 1.

[0015] This can be avoided by using a small enough amount of conductivepaste that only one side of the chip-like electronic part receives thepaste during any single application. However, this will necessitate fourseparate applications of the conductive paste which is not efficient.

SUMMARY OF THE INVENTION

[0016] It is an object of the present invention to provide a process offorming an electrode of a chip-like electronic part and a holder for achip-like electronic part used in the process which can resolve theabove described problem.

[0017] To this end, the process of the present invention forms anelectrode on a chip-like electronic part of the type having a centralaxis, a polygonal cross section as viewed in a plane which isperpendicular to the central axis, a plurality of side surfacesextending in respective planes which are generally parallel to thecentral axis, and a pair of end surfaces extending generally parallel tothe central axis, each adjacent pair of side surfaces meeting along arespective edge of the chip-like electronic part, the process comprisingthe steps of:

[0018] applying a first band of conductive material to at least one ofthe side surfaces; and

[0019] applying a second band of conductive material to the remainingside surface(s) in such a manner that the first and second bands meet atrespective ones of the edges and together form a continuous band ofconductive material extending around the outer periphery of thechip-type electronic part.

[0020] In the preferred embodiment, the first and second bands areapplied to the side surfaces at an area that lies between the endsurfaces, and more preferably in the middle, of the chip-like electronicpart and do not extend to either end surface.

[0021] In the preferred embodiment, the chip-like electronic part hasfour side surfaces, the first band is applied to first and secondcontiguous side surfaces and the second band is applied to third andfourth contiguous side surfaces by bringing the side surfaces intocontact with strips of conductive paste. The chip-like electronic partis first held in a holder with the first and second side surfacesextending outwardly from the holder and the first band is applied to thefirst and second side surfaces by moving a strip of conductive pastelocated on an elastic paste base into contact with the first and secondside surfaces. Thereafter, the orientation of the chip-like electronicpart is changed by either moving it within the same holder or moving itto a second holder to ensure that the third and fourth side surfacesextend outwardly from the holder. Once in this position, the second bandis applied to the third and fourth side surfaces by moving a strip ofconductive paste located on an elastic paste base into contact with thethird and fourth side surfaces.

[0022] When desired, the first and second bands can be applied to theside surfaces at an area of the side surfaces located adjacent one ofthe end surfaces thereof and can simultaneously be applied to theadjacent one of the end surfaces as well as the side surfaces.

[0023] The process of the present invention can also be used to place aplurality of electrodes on a chip-like electronic part having a centralaxis, a polygonal cross section as viewed in a plane which isperpendicular to the central axis, a plurality of side surfacesextending in respective planes which are generally parallel to thecentral axis, and a pair of end surfaces extending generally parallel tothe central axis, each adjacent pair of side surfaces meeting along arespective edge of the chip-like electronic part. In such a case, theprocess preferably comprising the steps of:

[0024] applying a set of first bands of conductive material to at leastone of the side surfaces, each of the first bands being applied at adifferent axial position on the side surfaces so as to be spaced fromone another; and

[0025] applying a set of second bands of conductive material to theremaining side surface(s) , each of the second bands being applied at adifferent axial position of the remaining side surfaces so as to bespaced from one another, each band of the first set meeting a respectiveband of the first set at two respective edges such that each respectivepair of bands forms a continuous band of conductive material extendingaround the outer periphery of the chip-type electronic part. Morepreferably, the chip-like electronic part has four side surfaces and isin the form of a quadrangular prism.

[0026] In the preferred embodiment, three continuous bands are formed,two adjacent the end surfaces of the chip-like electronic part, thethird at a position intermediate the two end surfaces of the chip-likeelectronic part. The bands of conductive material are applied to theside surfaces by bringing them into contact with strips of conductivepaste. In the preferred embodiment, the first applying step is carriedout by holding the chip-type electronic part in a holder with the firstand second side surfaces extending outwardly from the holder and thefirst set of bands are applied to the first and second side surfaces bymoving a plurality of strips of conductive paste located on an elasticpaste base into contact with the first and second side surfaces.Similarly, the second applying step is carried out by holding thechip-type electronic part in a holder with the third and fourth sidesurfaces extending outwardly from the holder and the second set of bandsis applied to the third and fourth side surfaces by moving a pluralityof strips of conductive paste located on an elastic paste base intocontact with the third and fourth side surfaces. The same or differentholders can be used for the first and second applying steps.

[0027] According to a further aspect of the process of the presentinvention, an electrode is formed on each of a plurality of chip-likeelectronic parts of the type having a central axis, a polygonal crosssection as viewed in a plane which is perpendicular to the central axis,a plurality of side surfaces extending in respective planes which aregenerally parallel to the central axis, and a pair of end surfacesextending generally parallel to the central axis, each adjacent pair ofside surfaces meeting along a respective edge of the chip-likeelectronic part, and the process comprises the steps of:

[0028] simultaneously applying a first band of conductive material to atleast one of the side surfaces of each of the chip-like electronicparts; and

[0029] simultaneously applying a second band of conductive material tothe remaining side surface(s) of each of the chip-like electronic partsin such a manner that the first and second bands of a respectivechip-like electronic part meet at respective ones of the edges on thatchip-like electronic part and together form a continuous band ofconductive material extending around the outer periphery of thatchip-type electronic part.

[0030] In the preferred embodiment, each of the chip-like electronicparts has four side surfaces and each of the first bands is applied tofirst and second contiguous side surfaces and wherein each of the secondbands is applied to the remaining two side surfaces by bringing the sidesurfaces into contact with strips of conductive paste. The firstapplying step is carried out by holding each of the chip-type electronicparts in a single holder with the first and second side surfaces of eachchip-like electronic part extending outwardly from the holder and thefirst band is applied to the first and second side surfaces of each ofthe chip-like electronic parts by moving respective strips of conductivepaste located on an elastic paste base into contact with the first andsecond side surfaces. The second applying step is carried out by holdingeach of the chip-type electronic parts in a single holder with the thirdand fourth side surfaces extending outwardly from the holder and thesecond band is applied to the third and fourth side surfaces by movingstrips of conductive paste located on an elastic paste base into contactwith the third and fourth side surfaces. Again, a single or multipleholders can be used.

[0031] The present invention is also directed toward a combination,comprising:

[0032] a chip-like electronic part having a plurality of outer surfacesextending generally parallel to a central axis of the chip-likeelectronic part, at least one of the surfaces having a band ofconductive material located thereon; and

[0033] a holder holding the chip-like conductive part in an orientationwherein at least one of the outer surfaces of the chip-like electronicpart extends outwardly from the holder and wherein the surface(s) of thechip-like electronic part which have the band of conductive materiallocated thereon face inwardly of the holder and are not exposed.

[0034] In the preferred embodiment, the holder includes a recess inwhich the band of conductive material is located without the conductivematerial touching the walls of the recess. The holder has a groove,including a plurality of side walls, for holding the electronic part,the shape of the groove corresponding generally to the shape of theportion of the chip-like electronic part being held in the groove. Thewalls of the chip-like electronic part which have the band of conductivematerial formed thereon are preferably in contact with the side walls ofthe groove and the band of conductive material itself is situated in arecess formed in the groove such that the band of conductive materialdoes not contact the walls of the groove or the walls of the recess.When the chip-like electronic part is formed in a shape of aquadrangular prism, the groove is formed in a V-like shape.

[0035] The present invention is also directed towards a chip-likeelectronic part comprising:

[0036] a main body portion having a central axis, a polygonal crosssection as viewed in a plane which is perpendicular to the central axis,a plurality of side surfaces extending in respective planes which aregenerally parallel to the central axis, and a pair of end surfacesextending generally parallel to the central axis, each adjacent pair ofside surfaces meeting along a respective edge of the main body portion;

[0037] a pair of end electrodes located on the end surfaces of the mainbody portion; and

[0038] a central electrode comprising a sintered metal formed of anelectrode paste and extending over each of the side surfaces of the mainbody portion so as to extend entirely around the outer periphery of themain body portion, the central electrode being formed of two bands ofsintered conductive paste, the two bands meeting at respective edges ofthe main body portion.

[0039] The two respective edges are preferably located 180 degrees apartfrom one another as measured around the central axis of the main bodyportion with the two bands overlapping one another at the respectiveedges.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] For the purpose of illustrating the invention, there is shown inthe drawing a form which is presently preferred, it being understood,however, that the invention is not limited to the precise arrangementand instrumentality shown.

[0041]FIG. 1 is a perspective view of a chip-like electronic part 21 towhich a process of forming an electrode according to one embodiment ofthe present invention is applied.

[0042]FIG. 2 is a sectional view showing an inner electrode 25 of thechip-like electronic part 21 of FIG. 1;

[0043]FIG. 3 is a sectional view showing an inner electrode 26 of thechip-like electronic part 21 of FIG. 1.

[0044]FIG. 4 is a perspective view of a chip-like electronic part 21 ato which a process of forming an electrode according to other embodimentof the present invention is applied.

[0045]FIG. 5 is a front view showing a plurality of chip-like electronicparts 21 of FIG. 1 held by a holder 27.

[0046]FIG. 6 is a partial, enlarged front view showing a singlechip-like electronic part 21 held by the holder 27 of FIG. 5.

[0047]FIG. 7 is a side view showing a single chip-like electronic partbeing held by the holder 27 of FIG. 5 and also showing a section ofpaste base 39.

[0048]FIG. 8 is a view corresponding to FIG. 7 but in which a paste base43 is used in place of the paste base 39 of FIG. 7.

[0049]FIG. 9 is a view corresponding to FIG. 7 in which a slit plate 45is used in place of the paste base 39 of FIG. 7.

[0050]FIG. 10 a bottom view showing a portion of a holder 27 a which ispreferably used in a step of providing a conductive paste 41 at a secondtime.

[0051]FIG. 11 is a bottom view showing the chip-like electronic part 21being held by the holder 27 a of FIG. 10.

[0052]FIG. 12 is a sectional view taken along a line XII-XII of FIG. 11.

[0053]FIG. 13 is a sectional view schematically showing the chip-likeelectronic part 21 provided with conductive pastes 41 a and 41 b for thecentral electrode 4 of FIG. 1.

[0054]FIG. 14 is a view corresponding to FIG. 6 showing the chip-likeelectronic part 21 a of FIG. 4 being held by a holder 27 b.

[0055]FIG. 15 is a view corresponding to FIG. 8 for explaining anotherembodiment of the present invention.

[0056]FIG. 16A is a perspective view showing the chip-like electronicpart 21 after the conductive paste 41 has been applied to one-half ofthe electronic part after having been processed by the step shown inFIG. 15.

[0057]FIG. 16B is a perspective view showing the chip-like electronicpart 21 after the conductive paste 41 has been applied to all of theelectronic part.

[0058]FIG. 17 is a sectional view for explaining a further embodiment ofthe present invention and showing the chip-like electronic part 21 beingheld by a holder 27 c which is used in place of the holder 27 shown byFIG. 5 through FIG. 7.

[0059]FIG. 18 is a perspective view of a conventional chip-likeelectronic part 1 which is of interest for the present invention.

[0060]FIG. 19 is a view corresponding to FIG. 7 showing a step ofproviding a conductive paste 7 onto the chip-like electronic part 1 toform a central electrode 4.

[0061]FIG. 20 is a sectional view schematically showing the conductivepaste 7 extending along the entry periphery of the outer surface of thechip-like electronic part 1 using the process shown in FIG. 19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] Referring now to the drawings wherein like numerals indicate likeelements, there is shown in FIG. 1 a chip-like electronic part 21 onwhich a central electrode has been formed using a process correspondingto a first embodiment of the present invention. The chip-like electronicpart 21 is a quadrangular prism having a section which is substantiallysquare in shape. End electrodes 22 and 23 are respectively formed onopposite end surfaces of the chip-like electronic part 21 and a centralelectrode 24 is formed at the central portion thereof (as measured alongthe central axis of the part 21). The central electrode 24 is formed toextend around the entire periphery of the outer surface of the chip-likeelectronic part 21.

[0063] The chip-like electronic part 21 constitutes a three terminalcapacitor having at least one, and preferably a plurality, of innerelectrodes 25 defining a first group of inner electrodes (one of whichis shown in FIG. 2) and at least one, and preferably a plurality, ofinner electrodes 26 defining, a second group of inner electrodes (one ofwhich is shown in FIG. 3). Individual electrodes of the first and secondgroups are arranged alternately to one another so as to be interleaved.As shown in FIG. 2, the inner electrodes 25 of the first group arecoupled to the end electrodes 22 and 23. As shown in FIG. 3, the innerelectrodes 26 of the second group are coupled to the central electrode24. The electrostatic capacitances formed between the inner electrodes25 of the first group and the inner electrodes 26 of the second groupcan be taken out between the end electrode 22 or 23 and the centralelectrode 24. The chip-like electronic part 21 can be used, for example,to remove noise on a signal line by interposing the end electrodes 22and 23 in the signal line and grounding the central electrode 24.

[0064] The process of the present invention can also be used to applythe central electrode to the chip-like electronic part 21 a of FIG. 4.Chip-like electronic part 21 a is substantially similar to chip-likeelectronic part 21 of FIG. 1 except that it has a rectangular crosssection. Since the structure is otherwise the same, no furtherdescription is provided.

[0065] An explanation will be provided of a process of forming thecentral electrode 24 of the chip-like electronic part 21 shown by FIG. 1with reference to FIG. 5 through FIG. 13. Because the end electrodes 22and 23 are normally formed after the central electrode 24 is formed inFIG. 5 through FIG. 9 and FIG. 11 through FIG. 13, the end electrodes 22and 23 of the chip-like electronic part 21 are not illustrated. However,this is not necessarily the case and the central electrode 24 may beapplied after the end electrodes 22 and 23 have already been formed.

[0066] Referring to FIG. 5, a holder 27 adapted to hold a plurality ofthe chip-like electronic parts is attached to a rigid base. An enlargedview of a portion of the holder 27 is shown in FIG. 6.

[0067] The holder has a plurality of holding portions 33 for holding aplurality of the chip-like electronic parts 21. Each chip-likeelectronic part 21 has at least two outer surfaces facing outward sothat a portion of the central electrode can be applied thereto. Moregenerally, a portion of the outer surface corresponding to an arc of atleast 180° around the center axis of the part 21 is exposed. In theexample shown, two side faces 31 and 32, located on opposite sides ofedge line 30, are exposed. Each of the holding portions 33 is preferablyprovided with a holding groove 34 for receiving the non-exposed surfacesof the chip-like electronic part 21. The holding groove 34 has a contactface 35 against which the non-exposed surfaces 37 and 38 of thechip-like electronic part 21 rest. Since the chip-like electronic part21 has a square cross-section the contact face 35 has a V-like shape.

[0068] The holder 27 is formed, for example, from an elastic body. Thecontact face 35 adheres to the chip-like electronic part 21 to hold itin place. This can be achieved by any suitable means such as by vacuumsucking.

[0069] Next, as shown in FIG. 7, a groove 40 located in an elastic pastebase 39 is filled with a conductive paste 41 to form a paste streak 42(paste extending in a shape of a streak). The chip-like electronic part21 is held by the holder 27 in an orientation wherein the paste streak42 extends orthogonal to the central axis of the chip-like electronicpart 21 and is positioned at a location corresponding to the middle ofthe chip-like electronic part 21. The holder 27 and the paste base 39are brought into contact with one another so that the paste base 39 isdeformed and presses against the outer side surfaces 31, 32 of thechip-like electronic part 21 and conductive paste 41 from the pastestreak 42 is applied to the side surfaces 31, 32 as shown in phantom inFIG. 7.

[0070] In accordance with this step of the process, a band of conductivepaste 41 is provided on the contiguous side faces 31 and 32 but is notapplied to the opposite side faces 37 and 28. Similarly, the conductivepaste does not stain the holder 27. The resultant band of conductivepaste 41 is shown in FIG. 13 as band 41 a.

[0071] Two non-limiting alternative process of forming the conductivepaste streak 42 are shown in FIGS. 8 and 9.

[0072] In the embodiment of FIG. 8, the conductive paste 41 is appliedto the flat face of the paste base 43 which may be an elastic or rigidbody. If it is a rigid body, it may be necessary to rotate the part 21back and forth about its longitudinal axis to bring the two oppositeside faces 31 and 32 into contact with the paste streak 42. Theconductive paste 41 may be built up onto the surface of the paste base43 by printing or the like to form a conductive paste streak 42.

[0073] In the embodiment of FIG. 9, a supply of conductive paste 41 isarranged on one side of a plate 45 having an elongated slit 44 (whichmay be rigid or deformable) and is extruded through the slit 44 to forma conductive paste streak 42.

[0074] The paste base 39 of FIG. 7 and the paste base 43 of FIG. 8 arepreferably deformed more easily than the elastic body constituting theholder 27 to avoid undesirable deformation of the holder 27.

[0075] Once the conductive paste 41 has been applied to the faces 31, 32of the chip-like electronic part 21, the part 21 is either transferredto a second holder or removed from the first holder, rotated, andreturned thereto, for application of conductive paste to the remainingtwo side faces 37 and 38. The second holder may have a structure similaror identical to that of the holder 27. In any event, the chip-likeelectronic part 21 is held by the holder so that the coated sidesurfaces 31, 32 face inwardly (are not exposed) and the remaining faces37, 38 face outwardly as shown in FIG. 12. In the preferred embodiment,two substantially similar holders are used and the transfer takes placeby positioning the two holders opposite one another and simultaneouslytransferring the plurality of the chip-like electronic parts 21 from thefirst holder to the second holder in a single motion.

[0076] In the case where the second holder is used as described above,it is preferable to use a holder 27 a shown in FIG. 10 through FIG. 12.Holder 27 a is provided with a recess portion 46 which accommodates theband of conductive paste 41 applied to the side surfaces 31, 32 andprevents the holder 27 a from being brought into contact with theconductive paste 41 on these sides. This prevents the band of conductivepaste 41 from being peeled off and the holder 27 a from being stained bythe conductive paste 41. The width of the recess portion 46 ispreferably wider than that of the band of conductive paste 41. Thestructure of the holder 27 a is otherwise substantially similar to thatof the holder 27 and a further explanation will not be provided. Thisholder may be used with any of the foregoing paste bases, for example,that of FIG. 7.

[0077] As shown in FIGS. 11 and 12, the holder 27 a holds the chip-likeelectronic part 21 with the uncoated side surfaces 37, 28 facingoutwardly and with the band of conductive paste 41 located on sidesurfaces 31, 32 positioned inside of the recess portion 46. Theconductive paste 41 is then applied to the exposed side surfaces 37, 38in accordance with any of the process described above. When this processis completed, the band of conductive paste 41 will extend around theentire periphery of the chip-like electronic part as illustrated in FIG.13 without the formation of build up (e.g. overlap) areas in the centralportions of the side faces 31, 32, 37 and 38 such as are created whenusing the prior art processes. Compare FIGS. 13 and 20. By curing theconductive pastes 41 a and 41 b, the desired central electrode 24 asshown by FIG. 1 is formed.

[0078] To form the end electrodes 22 and 23 at respective end portionsof the chip-like electronic part 21, the end portion of the chip-likeelectronic part 21 may be dipped into a tank of conductive paste andthereafter, the conductive paste is cured. It is preferable that thecuring operation be carried out simultaneously with the curing operationfor forming the central electrode 24 mentioned above.

[0079] When forming the central electrode 24 on a chip-like electronicpart 21 b having a rectangular cross section, a holder 27 b (FIG. 14) isused. This holder has a holding groove 34 b whose shape corresponds tothat of the chip-like electronic part 21 b. More particularly, theholding groove 34 b has the shaped right triangle dividing the crosssectional profile of the chip-like electronic part 21 a diagonally. Thestructure and operation of holder 27 b is otherwise the same as holder27 and no further description will be provided.

[0080] In the foregoing embodiments, the end electrodes 22, 23 arepreferably formed by dipping. However, they can also be formed by, forexample, using a process similar to that used to form central electrode24 as shown in FIGS. 15 and 16.

[0081] As shown in FIG. 15, three conductive paste streaks 42 a, 42 band 42 c are formed on an elastic paste base 43 at areas correspondingto the central portion and end portions of the chip-like electronic part21. In the embodiment shown, the conductive paste streaks 42 a, 42 b and42 c, are placed on a flat surface of the paste base 43. Other processessuch as that of FIGS. 7 and 9 can also be used. Whichever process isused, the holder 27 and paste base 43 are moved toward one another tobring the conductive paste streaks 42 a, 42 b and 42 c into contractwith the side surfaces 31, 32 of the chip-like electronic part 21 whilethe paste base 43 is deformed to surround those side surfaces. As aresult, as shown in FIG. 16A, band of conductive paste 41 is applied tothe outer surfaces 31, 32 as well as one half of the end surfaces of thechip-like electronic part 21.

[0082] The chip-like electronic part 21 is then held in an orientationwherein the two uncoated side faces 37 and 38 are exposed and a coatingof conductive paste 41 is applied to the side surfaces 37, 38 as well asthe remaining end surfaces using the foregoing process to form threebands of conductive paste 41 extending around the entire periphery ofthe part 21 and corresponding to a central electrode 24 and two endelectrodes 22 and 23.

[0083] As shown in FIG. 16B, the conductive paste 41 is applied to allareas where end electrodes 22 and 23 and the central electrode 24 shouldbe formed. Overlapping portions X are formed in the end electrodes 22,23 and the central electrode 24 as a result of the conductive paste 41being applied as described above. Finally, the conductive paste 41 iscured, thereby forming the end electrodes 22, 23 and the centralelectrode 24. The overlapping portions X of the conductive paste areswollen after the conductive paste 41 as has been cured.

[0084] If desired, the foregoing process may be used to form just theend electrodes 22, 23 of the chip-like electronic part 21 in which caseonly the conductive paste streaks 42 b and 42 c (FIG. 15) are formed onthe paste base.

[0085] In lieu of the foregoing holders which contain a holding groove,the holder 27 c of FIG. 17 may be used (indeed any suitable holder maybe used to carry out the process of the present invention). Holder 27 chas a holding hole 47 for holding the chip-like electronic part in therequired orientation. At least an inner peripheral face portion 48 ofthe holding hole 47 is elastic. The chip-like electronic part 21 is heldin a desired orientation by elastically sandwiching opposite end facesof the chip-like electronic part 21 extending perpendicular to the hole47.

[0086] In the foregoing embodiments, the process of the presentinvention is applied to a chip-like electronic part 21 or 21 a in theshape of a quadrangular prism. However, the process of the presentinvention can be used with other chip-like electronic parts such asthose having a polygonal or a cylindrical shape. In the case of thechip-like electronic part having a cylindrical shape, one of generatorspresent on the outer surface constitutes one edge line. Additionally,the present invention is applicable to a chip-like electronic part otherthan the three terminal capacitor.

[0087] The present invention may be embodied in other specific formswithout departing from the spirit or essential attributes thereof and,accordingly, reference should be made to the appended claims, ratherthan to the foregoing specification, as indicating the scope of theinvention.

What is claimed is:
 1. A combination, comprising: a chip electronic parthaving a plurality of outer surfaces extending generally parallel to acentral axis of the chip electronic part, at least one of the surfaceshaving a band of conductive material located thereon; and a holderholding the chip conductive part in an orientation wherein at least oneof the outer surfaces of the chip electronic part extends outwardly fromthe holder and wherein the surface(s) of the chip electronic part whichhave the band of conductive material located thereon face inwardly ofthe holder and are not exposed.
 2. The combination of claim 1 , whereinthe holder includes a recess in which the band of conductive material islocated without the conductive material touching the walls of therecess.
 3. The combination of claim 1 , wherein the holder has a groove,including a plurality of side walls, for holding the electronic part,the shape of the groove corresponding generally to the shape of theportion of the chip electronic part being held in the groove.
 4. Thecombination of claim 3 , wherein the walls of the chip electronic partwhich have the band of conductive material formed thereon are in contactwith the side walls of the groove and the band of conductive materialitself is situated in a recess formed in the groove such that the bandof conductive material does not contact the walls of the groove or thewalls of the recess.
 5. The combination of claim 3 , wherein the chipelectronic part is formed in a shape of a quadrangular prism and thegroove is formed in a V-like shape.
 6. A chip electronic partcomprising: a main body portion having a central axis, a polygonal crosssection as viewed in a plane which is perpendicular to the central axis,a plurality of side surfaces extending in respective planes which aregenerally parallel to the central axis, and a pair of end surfacesextending generally parallel to the central axis, each adjacent pair ofside surfaces meeting along a respective edge of the main body portion;a pair of end electrodes located on the end surfaces of the main bodyportion; and a central electrode comprising a sintered metal formed ofan electrode paste and extending over each of the side surfaces of themain body portion so as to extend entirely around the outer periphery ofthe main body portion, the central electrode being formed of two bandsof sintered conductive paste, the two bands meeting at respective edgesof the main body portion.
 7. The chip electronic part of claim 6 ,wherein the two respective edges are located 180 degrees apart from oneanother as measured around the central axis of the main body portion. 8.The chip electronic part of claim 7 , wherein the two bands overlap oneanother at the respective edges.